During the coming semester we expect the New Control System (NCS) to
go into operation. CAMAC interfaces and VAX computers will finally be
retired. Hardware control will be through VME based systems, mostly
running Linux, and all user-interface and data processing software will
run on Linux.

The transition to the NCS is planned in two major steps. First,
starting in the second half of September, NCS version 1 will be
installed and tested, supporting a subset of features identified as
``essential''. Most current observing modes, including on-off, wobbler
switching, and on-the-fly maps, will be available for bolometers,
single-pixel SIS receivers, and HERA. We are reviewing a detailed list
of these ``essential'' features of NCS v1 and will publish it on the IRAM
web site.

Other observing modes and new features will be made available in a
second step, for which the details and timing will depend in part on
the demands of the new proposals. We therefore expect that a few
proposals requesting rare observing modes not included in NCS v1, may
experience scheduling constraints.

Working with the NCS will be easy for observers used to the current
control system, although some commands will change in order to support
new features. A user's guide for the NCS will be available before any
projects get scheduled under the NCS, and we will provide special
support for observations with the NCS.

The extended tuning range of the 3mm receivers (down to 77 GHz
in LSB with good USB rejection, and near-DSB operation in the 72 -
77 GHz range) is now routinely available, with the proviso that
a 1.3mm receiver housed in the same dewar as a 3mm receiver used
below 80 GHz is not available. No hardware modifications
are needed anymore. However, due to the rapid variation (with
frequency) of the
sideband ratio, special care must be taken with calibration. Recipes
are described in a test report (available at
./IRAMFR/PV/veleta.htm). The report also
contains a collection of 72 - 80 GHz reference spectra.
Proposers should use the time estimator which will include the correct
receiver temperature at the low frequencies and an extra overhead for
calibration.

The dual polarization HERA started to give satisfactory results
at the time of writing. The necessary expansion
of the IF distribution system is made, and the backend WILMA has been
debugged. Residual problems (one dead detector, some instabilities)
will be investigated this spring.

Like last summer, a bolometer array, most likely the 117-channel
MAMBO II which should be used for observing time estimates, will be
available. Somewhat depending on the LST ranges
requested by the new proposals, one or more smaller sessions of pooled
observations will be scheduled.

On the official cover page, please fill in the line `special requirements'
if you request either polarimetric observations,
service or remote observing. If the observations need or have to avoid
specific dates, enter them here.
If there are periods when you cannot
observe for personal reasons, please specify them here.

We insist upon receiving, with proposals for heterodyne receivers,
a complete list of frequencies corrected for source redshift (to 0.1 GHz)
and precise positions. If in very special cases the proposers do not feel
to be in a position to give this information,
they should take up contact
with the scheduler (thum@iram.fr).
The proposers should also specify on the cover sheet which receivers they
plan to use.

In order to avoid useless duplication of observations and to protect already
accepted proposals, we keep up a computerized list of targets.
We ask you to fill out carefully the source list in J2000 coordinates.
This list must contain all the sources (and only those
sources) for which
you request observing time. To allow electronic scanning of your
source parameters, your list must adhere to the format indicated on the
proposal form (no hand writing, please).
If your source list is longer (e.g. more than 15 sources) than what
fits onto the cover page, please use the LATEXmacro \extendedsourcelist.

A scientific project should not be artificially cut into several small
projects, but should rather be submitted as one bigger project, even if
this means 100-150 hours.

If time has already been given to a project but turned out to be
insufficient, explain the reasons, e.g. indicate the amount of time
lost due to bad weather or equipment failure; if the fraction of time
lost is close to 100%, don't rewrite the proposal, except for an
introductory paragraph. For continuation of proposals having led to
publications, please give references to the latter.

A handbook (``The 30m Manual'')
collects most of the information
necessary to plan 30m telescope observations[6].
The report entitled ``Calibration of spectral line data at the IRAM 30m
telescope''
explains in detail the applied calibration procedure. Both documents can be
retrieved from the URL ./IRAMES/otherDocuments/manuals/index.html.
A catalog of well calibrated spectra for a range of sources and transitions
(Mauersberger et al. [9]) is very useful for monitoring spectral
line calibration. A copy of the 30m file with the calibrated spectra can
be downloaded from the Spanish web site.

The astronomer on duty (whose schedule can be found at URL
./IRAMES/groups/astronomy/aodsched.html) should
be contacted well in advance of an observing run for any special
questions concerning the preparation of
an observing run (e.g. setup of on-the-fly maps etc).

Frequency switching is available for both HERA and the observatory's standard
SIS receivers. This observing mode is interesting for observations
of narrow lines where flat baselines are not essential, although
the spectral baselines with HERA are among the best known in frequency
switching. Certain limitations exist with respect
to maximum frequency throw ( km/s),
backends, phase times etc.; for a detailed report see [4].

This matter needs special attention as a serious time underestimate may be
considered as a sure sign of sloppy proposal preparation. We strongly
recommend to use the web-based Time Estimator
(URL: ./IRAMES/obstime/time_estimator.html),
whenever applicable. Versions 2.5 and higher handle
heterodyne (single pixel and HERA) as well as bolometer observations with
updated instrumental parameters.
Suggestions and questions can be addressed to Axel Weiß (aweiss@iram.fr).

If very special observing modes are proposed which
are not covered by the Time Estimator, proposers must give sufficient
technical details so that their time estimate can be reproduced.
In particular, the proposal must give values for ,
the spectral resolution, the expected antenna temperature of the signal,
the signal/noise ratio which is aimed for,
all overheads and dead times, and the resulting observing time.
A technical report explaining how to estimate the telescope time
needed to reach a given sensitivity level in various observing modes
was published in the January 1995
issue2of the IRAM Newsletter [5]. It has been included in the
30m telescope Manual [6].

Proposers should base their time request on normal
summer conditions, corresponding to 7mm of precipitable water vapor. Conditions during
afternoons can be degraded due to anomalous refraction. The observing
efficiency is then reduced and the temperature calibration is more uncertain
than the typical 10 percent.
If exceptionally good transmission or stability of the atmosphere
is requested which may be reachable only in
quasi-winter conditions, the
proposers must clearly say so in their time
estimate paragraph. Such proposals will however be particularly scrutinized.

As in the previous summer semester, we plan to pool
the bolometer and other suitable proposals together in one observing session,
probably in October.
The proposals participating in the pool
are observed by Granada staff and cooperating external astronomers,
coordinated by Axel Weiss. The participating proposals are grouped
according to their demand on weather quality, and they get observed
following the priorities assigned by the program committee. The organization
of the observing pool is described at ./IRAMES/observing/flexible/flexible.html.
Typically, the bolometer proposals are included in the pool,
but very weather sensitive heterodyne proposals may also request
inclusion in the pool. Bolometer and heterodyne proposals which are
particularly weather tolerant qualify as backup for the pool.
Participation in the pool is voluntary, and the respective box on the
proposal form should be checked.

To facilitate the execution of short (8 h) programmes, we
propose ``service observing'' for some easy to observe programmes
with only one set of tunings.
Observations are made by the local staff using precisely laid-out
instructions by the principal investigator.
For this type of observation, we request an acknowledgement
of the IRAM staff member's help in the forthcoming publication.
If you are interested by this mode of observing, specify it as
a ``special requirement'' in the proposal form. IRAM will then decide which
proposals can actually be accepted for this mode.

This observing mode
where the remote observer actually controls the telescope very much like
on Pico Veleta, is available from the downtown Granada office, from the
MPIfR in Bonn, from the ENS in Paris, from the OAN in Madrid (near Parque de Retiro),
and from IRAM in Grenoble. This observing mode is available
to projects without any particular technical demands and
to experienced 30m users. The prospective remote observer should note
``remote observing'' as a special requirement in the proposal cover sheet.

After time has been awarded to a proposal, the P.I. is requested
to give sufficient detail to the secretary, Cathy Berjaud (berjaud@iram.fr)
on how the remote observer can be contacted. Please note that IRAM is not
responsible for the remote stations in Paris, Madrid, or Bonn.

Remote observers affiliated with the MPIfR or other institutes near
Bonn should contact Dirk Muders (dmuders@mpifr-bonn.mpg.de)
at MPIfR for a short introduction to the remote observing station.
Remote observers in the Paris area may contact M. Gerin
(gerin@lra.ens.fr) for arrangements. Astronomers who want to use the
Madrid station are requested to contact Javier Alcolea
(j.alcolea@oan.es).
Remote observers in or near Grenoble please contact
H. Wiesemeyer (wiesemey@iram.fr) at IRAM.
Observers visiting the 30m might opt to do some of their observing from
Granada if it eases their travel constraints. In this case, a Granada
astronomer should be contacted as soon as possible, arrangements on very short
notice may not always be possible.

This section gives all the technical details of observations with the 30m
telescope that the typical user will have to know. A concise
summary of telescope characteristics is published on the IRAM web pages.

The HEterodyne Receiver Array is expected to be available
for most of next summer.
The 9 dual-polarization pixels are arranged in the form of a center-filled square
and are separated by . Each beam is split into two linear
polarizations (after a successful upgrade in March) which couple to
separate SIS
mixers. The 18 mixers feed 18 independent IF chains. Each set of
9 mixers is pumped by a separate local oscillator system. The same positions
can thus be observed simultaneously at any two frequencies inside the
HERA tuning range (210-276 GHz).

A derotator optical assembly can be set to keep the 9 pixel pattern
stationary in the equatorial or horizontal coordinates.
Receiver characteristics (of the single polarization system)
are listed in Tab. 1,
and an updated user manual (version 1.7) is available on our
web page.

Frequency tuning of HERA, although fully under remote control and automatic,
is substantially more complicated than for the
observatory's other SIS receivers. Although the tuning is still known
for only a few frequencies,
(the 3 CO isotopes at 230.5, 220.4, and 219.6
GHz; CS at 244.9 GHz; HCN at 265.9 GHz; HCO at 267.6 GHz; DCN and
HCN at 217.2 and 259 GHz; HCO at 225.7 GHz; H30 at 231.9
GHz), HERA proposals for any frequency within the nominal tuning
range of 210 - 276 GHz are encouraged. Despite good progress
being made with semi-automatic tuning procedures, there may still be
some difficult frequency spots. HERA observers are therefore well
advised to send a list of their frequencies to Granada at least 2
weeks ahead of their run.

HERA can be connected to three sets of backends:

VESPA with the following combinations
of nominal resolution (KHz) and maximum bandwidth (MHz):
20/40, 40/80, 80/160, 320/320, 1250/640. The maximum bandwidth can actually
be split into two individual bands for each of the 18 detectors
at most resolutions. These individual bands can be shifted separately
up to MHz offsets from the sky frequency
(see also the sections on backends below).

a low spectral resolution (4 MHz channel spacing) filter spectrometer
covering the full IF bandwidth of 1 GHz. Nine units (one per HERA pixel)
are available. Note that only one polarization of the full array is thus
connectable to these filter banks.

WILMA with a 1 GHz wide band for each of the 18 detectors.
The bands have 512 spectral channels spaced out by 2 MHz.
WILMA will be available after successful completion of the current tests.

HERA is operational in two basic spectroscopic observing modes:
(i) raster maps of areas typically not smaller than ,
in position, wobbler, or frequency switching modes, and
(ii) on-the-fly maps of moderate size (typically ).
Extragalactic proposals should take into account the current limitations
of OTF line maps, as described in the User Manual, due to baseline
instabilities induced by residual calibration errors.
HERA proposers should use the web-based
Time Estimator.
For details about observing with HERA, consult the User manual.
The HERA project scientist Karl Schuster (schuster@iram.fr),
or Albrecht Sievers (sievers@iram.es),the astronomer
in charge of HERA, may also be contacted.

Four dual polarization SIS receivers are available at the
telescope for the upcoming observing season.
They are designated according to the dewar in which they are
housed (A, B, C, or D), followed by the center frequency (in GHz) of their
tuning range.
Their main characteristics are summarised in Tab. 1. All receivers
are linearly polarized with the E-vectors, before rotation in the
Martin-Puplett interferometers, either horizontal or
vertical in the Nasmyth cabin.
Up to four of these eight receivers can be combined
for simultaneous observations in the four ways depicted in Tab. 1.
Note that they cannot be combined with HERA nor with the bolometers.
Also listed are typical system temperatures which apply to normal
summer weather (7mm of water)
at the center of the tuning range and at 45 elevation.
All receivers are tuned by the operators from the control room.
Experience shows that it normally takes not more than 15 min
to tune four such receivers.

Table 1:
Heterodyne receivers available for the next summer
observing semester. Performance figures are based on recent
measurements at the telescope.
is the SSB system
temperature in the scale at the nominal center of the
tuning range, assuming average summer conditions (pwv = 7mm) and 45 elevation. is the rejection factor of the image side band.
and
are the IF center frequency and
width.

Several molecules of high astrophysical importance have transitions in
the frequency band 66 - 80 GHz, i.e. between the atmospheric absorption
band and the low frequency edge of the nominal 3mm tuning range
(see Tab.1). Tests have shown that both 3mm receivers, A100
and B100 have good performance (good USB rejection and system
temperature) in the range 80 - 77 GHz. The receivers become
increasingly DSB below 77 GHz, until their behavior becomes erratic
around 72 GHz. Due to the rapid variation of the image gain, special
care must be exercised with calibration. A new image gain calibration
tool is provided and described in the test report
available on the IRAM web site
(at ./IRAMFR/PV/veleta.htm). The report includes
a set of reference spectra.

Following the considerable demand for this frequency range in the last
2 semesters, the LO hardware has been simplified. As a result,
observations in the 72 - 80 GHz range do not require any special
arrangements, except that the A230 (B230) receiver is unusable
when the A100 (B100) receiver is used below 80 GHz.

Tuning of the single pixel/dual polarization receivers is now
considerably faster and more reproducible than before.
Particular frequencies, like those in the range 72 - 80 GHz or
those near a limit of the tuning range,
may still be problematic. In these cases, we recommend
to check with a Granada receiver
engineer at least two weeks before the observations.
HERA observers, however, are requested to send their frequencies as
soon as their project gets scheduled.

An upgrade of the IF polarimeter [16]
is now available,
where the cross correlation between the IF signals from a pair of orthogonally
polarized receivers is made digitally in VESPA.
The new observing procedure, designated XPOL, generates simultaneous
spectra of all 4 Stokes parameters. The following combinations of
spectral resolution (kHz) and bandwidth (MHz) are available:
40/120, 80/240, 320/480, and 1250/640.

Although successful XPOL observations were made at several frequencies,
experience is still limited, particularly with respect to long integrations
and observations of extended sources.
Data reduction software using CLASS enhanced with a
graphical user interface is available (H. Wiesemeyer). A short guide
(at ./IRAMFR/PV/veleta.htm) describes XPOL observations.
Polarimetry proposals will be considered with the restriction that
the target sources be not larger than the main beam.

The bolometer arrays, MAMBO-1 (37 pixels) and MAMBO-2 (117 pixels),
are provided by the Max-Planck-Institut für Radioastronomie. They
consist of concentric hexagonal rings of horns
centered on the central horn. Spacing between horns is .
Each pixel has a HPBW of 11.
We expect that MAMBO-2 will be normally used, but MAMBO-1 is kept as
a backup.

The effective sensitivity of MAMBO-1 for onoff and mapping observations is
39 mJys.
For MAMBO-2 effective sensitivities of
46 mJys (ON/OFF mode) and
52 mJys (mapping mode)
were measured. The rms, in mJy, of a MAMBO-2 map is typically

where , in arcsec/sec, is the velocity in the scanning
direction and , in arcsec, is the step size in the
orthogonal direction. The factor is 1 (2) for sources of size
. It is assumed that the map is made large enough
that all beams cover the source.
The sensitivities apply to bolometric
summer conditions
(
0.3, elevation 45 deg, and application of skynoise filtering algorithms).
In cases where skynoise filtering algorithms
are not or not fully effective
(e.g. extended source structure, atmosphere not sufficiently stable),
the effective sensitivity is typically about a factor of 2 worse. For
those projects, only atmospheric conditions with
low skynoise (i.e. stable atmosphere, no clouds,
little turbulence) are recommened unless the
expected signal is about 1 Jy/beam or stronger.

The bolometer arrays are mostly used in two basic observing modes, ON/OFF and
mapping. Previous experience with MAMBO-2 shows that the ON/OFF reaches
typically an rms noise of mJy in 10 min of total observing time
(about 200 sec of ON source, or about 400 sec on sky integration time)
under stable conditions.
Up to 30 percent lower noise may be obtained in perfect weather.
In this observing mode, the noise integrates down with time as
to rms noise levels below 0.5 mJy.

In the mapping mode, the telescope is scanning in the
direction of the wobbler throw (default: azimuth) in such a way
that all pixels see the source once.
A typical single map3
with MAMBO-2 covering a fully and homogeneously sampled area of
(scanning speed: per sec, raster step: )
reaches an rms of 2.8 mJy/beam in 1.9 hours if skynoise filtering is effective.
Much more time is needed (see Time Estimator) if sky noise filtering cannot be
used.
The area actually scanned (
) must be larger than the map size
(add the wobbler throw and the array size (), the source extent,
and some allowance for baseline determination)
if the EHK-algorithm is used to restore properly extended emission.
Shorter scans may lead to problems in
restoring extended structure. Mosaicing is also
possible to map larger areas. Under many circumstances,
maps may be co-added to reach lower noise levels.
If maps with an rms
mJy are proposed, the proposers should
contact the experts.

The bolometers are used with the wobbling secondary mirror
(wobbling at a rate of 2 Hz). The wobbling direction which used to be
fixed in azimuth, can now be freely chosen within some limits (see
IRAM Newsletter No. 61). This allows in virtually all cases to adapt
the wobbling/scanning direction to the source under study.
Nevertheless, the orientation of the beams on the sky changes with
hour angle due to parallactic and Nasmyth rotations, as the array is
fixed in Nasmyth coordinates and the wobbler direction is fixed with
respect to azimuth during a scan.
Bolometer proposals participating in the pool have their observations
(maps and ONOFFs)
pre-reduced by a data quality monitor which runs scripts in the newly developed
MOPSIC. This package, complete with all necessary scripts,
is also installed for off-line data analysis in Granada
and Grenoble. It is also available for distribution from the IRAM Data Base for
Pooled Observations or directly from R. Zylka (zylka@iram.fr).
The older software packages (NIC [7] and MOPSI[8])
are still available, but will not be updated.

Bolometer proposals will be pooled together like in previous
semesters along with suitable heterodyne proposals as long as the respective
PIs agree.
The web-based time estimator handles well the usual bolometer observing
modes, and its use is again strongly recommended. The time estimator uses
rather precise estimates of the various overheads which will be applied
to all bolometer proposals.
If exceptionally low noise levels are requested which may be reachable only
in a perfectly stable (quasi-winter)
atmosphere, the proposers must clearly say so in their time estimate
paragraph. Such proposals will however be particularly scrutinized.
On the other extreme, if only strong sources are observed and moderate
weather conditions are sufficient,
the proposal may be used as a backup in the observing pool. The
proposal should point out this circumstance, as it affects positively the
chance that the proposal is accepted and observed.

Table 2 lists the size of the telescope beam for the
range of frequencies of interest. Forward and main beam efficiencies
are also shown (see also the note by U. Lisenfeld and A. Sievers, IRAM
Newsletter No. 47, Feb. 2001). The variation of the
coupling efficiency to sources of different sizes can be estimated from
plots in Greve et al. [12].

At 1.3 mm (and a fortiori at shorter wavelengths) a large
fraction of the power pattern is distributed in an error
beam which can be approximated by two Gaussians of FWHP
and (see [12] for details).
Astronomers should take into account this error beam when converting
antenna temperatures into brightness temperatures.
A variable and sometimes large contribution to the error beam was known
to come from telescope astigmatism[3].
Extensive work during the last years had shown that the astigmatism resulted
from temperature differences between the telescope backup structure and
the yoke. The recent installation of heaters in the yoke by J. Peñalver
has nearly completely removed the astigmatism[15].

With the systematic use of inclinometers the telescope pointing became
much more stable. Pointing sessions are now scheduled at larger intervals.
The fitted pointing parameters typically yield an absolute rms pointing
accuracy of better than [10]. Receivers are closely
aligned (within ).
Checking the pointing, focus, and receiver alignment is the
responsibility of the observers (use a planet for alignment checks).
Systematic (up to 0.4 mm) differences between the foci of various receivers
can occasionally occur.
In such a case the foci should be carefully monitored and a compromise value
be chosen. Not doing so may result in broadened and
distorted beams ([1]).

Backends

The following four spectral line backends are available which can be
individually connected to any single pixel receiver and, if indicated,
also to HERA.

The 1 MHz filterbank consists of 4 units. Each unit has 256
channels with 1 MHz spacing and can be connected to different or
the same receivers giving bandwidths
between 256 MHz and 1024 MHz. The maximum bandwidth is available
for only one receiver, naturally one having a 1 GHz wide IF bandwidth.
Connection of the filterbank in the 1 GHz mode presently excludes the
use of any other backend with the same receiver.

Other configurations of the 1 MHz filterbank include
a setup in 2 units of 512 MHz connected to two different receivers, or 4 units
of 256 MHz width connected to up to four (not necessarily) different receivers.
Each unit can be shifted in steps of 32 MHz relative to the center frequency
of the connected receiver.

The 100 KHz filterbank consists of 256 channels of 100 KHz spacing.
It can be split into two halves, each movable inside the 500 MHz IF
bandwidth, and connectable to two different single pixel receivers.

VESPA, the versatile spectrometric and polarimetric array,
can be connected either to HERA or to a subset of 4 single pixel receivers,
or to a pair of single pixel receivers for polarimetry.
The many VESPA configurations and user modes are summarized in a
Newsletter contribution
[14] and in a
user guide,
but are best visualised on a demonstration program which can be downloaded
from our web page
at URL ./IRAMFR/PV/veleta.htm.
Connected to a set of 4 single pixel receivers VESPA typically provides up to
12000 spectral channels (on average 3000 per receiver).
Up to 18000 channels are possible in special
configurations. Nominal spectral resolutions range from 3.3 KHz
to 1.25 MHz. Nominal bandwidths are in the range 10 -- 512 MHz.
When VESPA is connected to HERA, up to 18000 spectral channels can be used
with the following typical combinations
of nominal resolution (KHz) and maximum bandwidth (MHz):
20/40, 40/80, 80/160, 320/320, 1250/640.

The 4 MHz filterbank consists of nine units.
Each unit has 256 channels (spacing of 4 MHz, spectral resolution at 3 dB
is 6.2 MHz) and thus covers a total bandwidth of 1 GHz.
The 9 units are designed for connection to HERA, but a subset of 4 units
can also be connected to the backend distribution box which feeds
the single pixel spectral line receivers. All these receivers have a 1 GHz RF
bandwidth except for A100 and B100 (500 MHz only).
At the present time, a 4 MHz filterbank cannot be used simultaneously with
the autocorrelator or the 100 KHz filterbank on the same receiver.

An on-line calibration routine automatically writes calibrated
spectrometer data, including the 4 MHz filterbanks,
to the Linux machines. The routine, although still experimental, works
for all observing modes. A logical link named ``data.30m'' pointing to this file of calibrated spectra
is made available in all newly created project accounts.

The wideband autocorrelator WILMA consists of 18 units. They can
be connected to the 18 detectors of HERA. Each unit provides 512 spectral channels, spaced
out by 2 MHz and thus covering a total bandwidth of 1 GHz. Each band is sliced
into two 500 MHz subbands which are digitized with 2 bit/1GHz samplers.
An informative technical overview of the architecture is
available on the web page
(URL: ../IRAMFR/TA/backend/veleta/wilma/index.htm).

WILMA can be connected to the 18 detectors of HERA or, with 4 units
maximum, to the single pixel receivers.